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Sophia Terres, Lucas Scalon, Julius Brunner, Dominik Horneber, Johannes Düreth, Shiyu Huang, [Takashi Taniguchi](https://orcid.org/0000-0002-1467-3105), [Kenji Watanabe](https://orcid.org/0000-0003-3701-8119), Ana Flávia Nogueira, Sven Höfling, Sebastian Klembt, Yana Vaynzof, Alexey Chernikov

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[Exciton Diffusion in Two‐dimentional Chiral Perovskites](https://mdr.nims.go.jp/datasets/250da6e8-54c4-4fad-8684-ec36b8401938)

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Exciton Diffusion in Two‐dimentional Chiral PerovskitesRESEARCH ARTICLEwww.advopticalmat.deExciton Diffusion in Two-dimentional Chiral PerovskitesSophia Terres, Lucas Scalon, Julius Brunner, Dominik Horneber, Johannes Düreth,Shiyu Huang, Takashi Taniguchi, Kenji Watanabe, Ana Flávia Nogueira, Sven Höfling,Sebastian Klembt, Yana Vaynzof, and Alexey Chernikov*Two-dimensional (2D) organic–inorganic hybrid perovskites emerged as aversatile platform for light-emitting and photovoltaic applications due to theirunique structural design and chemical flexibility. Their properties dependheavily on the choice of the inorganic lead halide framework and thesurrounding organic layers. Recently, the introduction of chiral cations into 2Dperovskites has attracted major interest to induce chirality and tune thechiro-optical response. Importantly, their optical properties are dominated bytightly bound excitons that also serve as primary carriers for energy transport.The mobility of photo-injected excitons is thus important from theperspectives of fundamental material properties and optoelectronicapplications, yet remains an open question. Here, exciton propagation in 2Dchiral perovskites is demonstrated using transient photoluminescencemicroscopy and density-dependent transport over more than 100 nanometersat room temperature is revealed with diffusion coefficients as high as 2cm2 s−1. Two distinct regimes of initially rapid propagation and subsequentlocalization are observed. Moreover, perovskites with enantiomer pure cationsexhibit faster exciton diffusion than the racemic mixture, correlated with theimpact of the material composition on the disorder. Altogether, theobservations of efficient exciton diffusion highlight the potential of 2D chiralperovskites to merge chiro-optical properties with strong light-matterinteraction and energy transport.S. Terres, A. ChernikovInstitute of Applied Physics and Würzburg-Dresden Cluster of Excellencect.qmatTUD Dresden University of Technology01062 Dresden, GermanyE-mail: alexey.chernikov@tu-dresden.deL. Scalon, J. Brunner, Y. VaynzofChair for Emerging Electronic TechnologiesTUD Dresden University of Technology01187 Dresden, GermanyL. Scalon, J. Brunner, Y. VaynzofLeibniz-Institute for Solid State and Materials Research Dresden01069 Dresden, GermanyThe ORCID identification number(s) for the author(s) of this articlecan be found under https://doi.org/10.1002/adom.202402606© 2025 The Author(s). Advanced Optical Materials published byWiley-VCH GmbH. This is an open access article under the terms of theCreative Commons Attribution License, which permits use, distributionand reproduction in any medium, provided the original work is properlycited.DOI: 10.1002/adom.2024026061. Introduction2D organic–inorganic hybrid perovskites,originally studied as early as the 1990s,[1–3]emerged as promising platforms forlight-emitting[4–6] and photovoltaicapplications.[7,8] These semiconductingmaterials feature an inorganic frameworksurrounded by organic layers with ex-ceptional chemical and structural designflexibility.[9] The inorganic layers comprisecorner-sharing lead halide octahedra andact as natural quantum wells hostingelectronic states forming the conductionand valence bands.[10] The organic cationsseparate the inorganic layers and serve pri-marily as electronic barriers,[11,12] while alsooffering the possibility to integrate a varietyof ammonium-based organic cations withdifferent functional groups[13,14] and spa-tial configurations.[15–18] The ammoniumgroups bind to the halide of the inorganicframework via hydrogen bonds, whilethe organic moieties interact through vander Waals and 𝜋-stacking interactions.[19]Recently, chiral organic cations wereembedded into perovskites to generateL. Scalon, A. F. NogueiraInstitute of ChemistryUniversity of Campinas (UNICAMP)Campinas, São Paulo 13083-970, BrazilD. Horneber, J. Düreth, S. Huang, S. Höfling, S. KlembtPhysikalisches Institut and Würzburg-Dresden Cluster of Excellencect.qmatLehrstuhl für Technische PhysikJulius-Maximilians-Universität WürzburgAm Hubland, 97074 Würzburg, GermanyT. TaniguchiResearch Center for Materials NanoarchitectonicsNational Institute for Material Science1-1 Namiki, Tsukuba 305-0044, JapanK. WatanabeResearch Center for Electronic and Optical MaterialsNational Institute for Materials Science1-1 Namiki, Tsukuba 305-0044, JapanAdv. Optical Mater. 2025, 13, 2402606 2402606 (1 of 9) © 2025 The Author(s). Advanced Optical Materials published by Wiley-VCH GmbHhttp://www.advopticalmat.demailto:alexey.chernikov@tu-dresden.dehttps://doi.org/10.1002/adom.202402606http://creativecommons.org/licenses/by/4.0/http://crossmark.crossref.org/dialog/?doi=10.1002%2Fadom.202402606&domain=pdf&date_stamp=2025-03-28www.advancedsciencenews.com www.advopticalmat.deFigure 1. a) Schematic illustration of the layered structure of the (n = 1) chiral perovskite MBA2PbI4, consisting of alternating organic (methylbenzy-lammonium, MBA) and inorganic layers (PbI4). Left panel: structure of the perovskite with enantiomer pure cations (S-MBA); right panel: perovskitestructure with racemic mixture (Rac-MBA). b) Chemical structure of the enantiomers R-MBA and S-MBA. c) Optical micrograph of a typical thin-layersample, encapsulated between 10′s of nm thick layers of h-BN. d) Representative room temperature PL spectra of both S/R-type samples and the racemicmixture at a moderately high excitation fluence of 0.7 μJ cm−2 using 140 fs pulses with photon energy of 3.02 eV. Gaussian fits to the high energy flankof the peaks are indicated by solid lines on top of the data. Intrinsic 2D exciton PL and that attributed to localized states and 1D phase incursions areindicated. e) Maps of the room temperature PL intensity, f) PL peak energy and g) linewidth of the same R-type sample depicted in panel (c) with 1 μmstep size, measured under continuous-wave 3.06 eV excitation.chiro-optical responses,[20,21] which is highly interesting forpolaritonics[22] and optospintronics.[23] Chiral cations wereshown to induce structural chirality transfer across the interfacebetween organic and inorganic units of 2D hybrid perovskitesby breaking the centrosymmetry of the crystal.[24] This changesthe electronic structure, introduces chiral polarization selectionrules,[20] and impacts phase purity and electronic disorder.[25]Moreover, this class of materials inherits the combination ofquantum confinement and reduced dielectric screening fromthe 2D perovskites, giving rise to strong Coulomb interactionsbetween the charge carriers. Consequently, excitons with bind-ing energies of several hundreds of meV form.[1,26,27] They rep-resent fundamental electron-hole excitations with strong light-matter coupling,[28] dominate the optical response[29] and, mostimportantly, serve as primary energy carriers in these systems.Transport of optically injected excitons in chiral 2D perovskitesis thus of major interest in the context of both fundamentalphysics of mobile and chiral many-body states and optoelec-tronic applications. In contrast to more conventional achiral 2Dperovskites[30,31] however, the exciton propagation in chiral com-pounds, the underlying mechanisms of either free or localizedtransport, and their relationship to the material structure remainunexplored.Here, we study exciton propagation in 2D chiral perovskitesvia transient photoluminescence microscopy. We observe linearand non-linear transport in samples with enantiomer pure (R-and S-configurations) cations and the racemic mixtures of bothcations. The excitons are found to exhibit initially rapid diffu-sive transport over more than 100 nanometers at room temper-ature, followed by localization at later times. In addition, exci-tons propagate faster for all studied densities in perovskites withenantiomer pure cations than their racemic mixture counter-part. These findings correlate with different energy scales of dis-order determined by photo-thermal deflection and hyperspatialspectroscopy.2. ResultsFor this study, we used thin-layer samples exfoliated from chi-ral 2D methylbenzylammonium lead iodide crystals (MBA2PbI4).The crystals were synthesized under a nitrogen atmosphere bydissolving lead (II) oxide (PbO) in hydrogen iodide (HI), followedby dropwise addition of R-, S- or rac-methylbenzylamine.[25] Fur-ther details about the synthesis as well as X-ray diffraction pat-terns of these crystals are presented (Figure S1, Supporting In-formation) can be found in the Supporting Information. Struc-tures of the enantiomer pure chiral 2D perovskite, as well as theracemic mixture, are schematically illustrated in Figure 1a. Enan-tiomer pure chiral cations induce the formation of asymmetrichydrogen bonds, creating symmetry-breaking distortions in theAdv. Optical Mater. 2025, 13, 2402606 2402606 (2 of 9) © 2025 The Author(s). Advanced Optical Materials published by Wiley-VCH GmbH 21951071, 2025, 11, Downloaded from https://advanced.onlinelibrary.wiley.com/doi/10.1002/adom.202402606 by National Institute For, Wiley Online Library on [20/08/2025]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons Licensehttp://www.advancedsciencenews.comhttp://www.advopticalmat.dewww.advancedsciencenews.com www.advopticalmat.deinorganic framework.[15,24,32] Chemical structures of the cationsproducing crystallographic right- (R-MBA) and left-handedness(S-MBA) are displayed in Figure 1b. In the racemic mixture, con-sisting of equal parts S-MBA and R-MBA cations, the hydro-gen bonds create symmetric tilting distortions, thus retaining thecentrosymmetry of the crystal.[19,24]The synthesized bulk crystals were micromechanically exfoli-ated, transferred onto SiO2/Si substrates using a polymer stamp,and encapsulated between hexagonal boron nitride (h-BN) lay-ers to ensure sample stability under illumination.[33] The result-ing samples comprised of perovskite crystals of a few hundrednanometers thickness with tens of nanometers thick h-BN layerswere placed in a microscopy cryostat for optical measurementsunder reduced pressure (<10−4 bar). We used a continuous-wavelaser with a photon energy of 3.06 eV for excitation in photolumi-nescence (PL) mapping and an 80 MHz, 140 fs pulsed Ti:sapphirelaser with a photon energy of 3.02 eV for time- and spatially-resolved PL measurements. They were performed at room tem-perature, and the incident laser beams were focused onto thesample by a 60x microscope objective, resulting in spot sizes ofabout 0.5 μm. The PL signal was then dispersed using a grat-ing or reflected by a mirror to obtain spectrally and spatiallyresolved responses. A CCD camera was used to record time-integrated signals and a streak camera was employed to moni-tor the time-resolved expansion of the emission area by imag-ing the luminescence cross-section along the x-coordinate. Addi-tional details regarding sample preparation, cryogenic circularlypolarized photoluminescence measurements and photo-thermaldeflection spectroscopy are given in the Supporting Information.2.1. Hyperspectral Mapping of Chiral 2D PerovskitesA micrograph of a studied thin-layer R-type sample encapsulatedbetween two layers of h-BN is shown in Figure 1c. Typical roomtemperature PL spectra of all three sample types are presentedin Figure 1d. They reveal the dominant 2D exciton signatureat ≈2.4 eV with an asymmetric shoulder on the lower energyside, commonly associated with localized states[34] and 1D phaseincursions.[35,36] While the use of the chiral cations enables thetransfer of chirality, it also leads to steric hindrance for the in-teraction of the ammonium group with the inorganic core. Thisresults in the formation of 1D moieties within the 2D perovskite,giving rise to broad-band emission at lower energies.[36,37]The position of the main exciton peak and the lower energyshoulder are found to depend on the sample position and theunderlying energy landscape, with variations up to a few tens ofmeV across the sample. We thus perform hyperspectral PL map-ping to assess spatial variations of the exciton spectral features onthe micrometer scale. Figure 1e–g displays maps of the PL inten-sity, peak energy and linewidth exemplary for an R-type sample(see SI for three additional R-type, S-type, and racemic mixturesamples). Each pixel on the map corresponds to an individual PLspectrum. The values for the different parameters are extractedfrom Gaussian fits to the high energy flank of the 2D excitonresonance as indicated by solid lines in the respective colors inFigure 2d. The map of the extracted PL intensity reveals spot-to-spot variations on the order of 50%. They are partially related tofluctuations in material thickness across the exfoliated sample,as observed by the changes of color due to interference effects inthe micrograph in Figure 1c. However, PL intensity also variesto a smaller degree in regions of seemingly uniform thickness,which is an observation not untypical for various 2D materials[38],including perovskites.[39] Analysis of the PL peak energy mapshows an energy landscape featuring both homogeneous areasof comparatively flat potentials with deviations of only a few meVover many μm, but also variations between them. We observe lo-cal energy shifts of the exciton resonance on the order of 10 to 20meV and overall shifts of up to 40 meV across the sample. Vari-ations in the total linewidth within one measurement spot areon the same order of magnitude, reasonably agreeing with theinhomogeneities in the energy distribution on the larger scale.The differences in the room temperature linewidths in Figure 1d,dominated by scattering with phonons[40], are most likely causedby the disorder on the mesoscopic scale, prevalent in the studiedchiral perovskites, as we show below. This represents the overallpotential landscape for the excitons to propagate in the studiedmaterial.2.2. Exciton DiffusionTo study exciton transport, we employ time- and spatially-resolved PL microscopy,[41,42] schematically illustrated inFigure 2a. Ultrafast laser pulses with excitation energy den-sities from 0.05 to 1.2 μJ cm−2 create a local distribution ofexcitons. The expansion of the light distribution emitted fromthe exciton cloud is then detected as a function of space andtime. A typical PL transient of an S-type sample recorded ata moderate excitation density of 0.7 μJ cm−2 is presented inFigure 2b. It features a fast decay of the exciton population overthe first several hundred ps after excitation and slower decaydynamics at later times. To analyze exciton transport acrossthese regimes, we extract the broadening 𝜎 of the PL emissionprofiles from a Gaussian fit of the form exp[− x2/2𝜎(t)2]. Theresulting mean squared displacement Δ𝜎2 = 𝜎2(t) − 𝜎2(0) ispresented in Figure 2c as a function of time and exhibits twodistinct propagation regimes.[43] At early times, we find a linearincrease in the exciton spatial distribution, characteristic ofdiffusive transport.[41] At later times, the broadening of the PLemission reaches saturation, defining a second regime wherethe absence of spatial expansion indicates the localization ofexcitons as they get trapped in lower-energy sites.[34]To analyze the subdiffusive behavior, we apply a model intro-duced by Seitz et al.[30] and Folie et al.[44], that considers initiallyfree exciton propagation, followed by localization due to perma-nent capture of the excitons by deep traps. The model allows forextraction of the diffusion coefficient D from the mean squareddisplacement according to Δ𝜎2 (t) = 2𝜆2eff [1 − exp(− D𝜆2efft)], where𝜆eff is an effective average distance between traps.[30] The modelwas initially proposed to test the influence of trap states on thediffusion behavior in perovskites with achiral cations where themagnitude of the subdiffusive regime was found to be depen-dent on background illumination and excitation density.[30,43,45]For the studied chiral 2D perovskites, the obtained value forthe diffusion coefficient of 1.2 cm2 s−1 is very similar to find-ings in (PEA)2PbI4,[43,46] in which the organic cation is a con-stitutional isomer of MBA, known to exhibit comparativelyAdv. Optical Mater. 2025, 13, 2402606 2402606 (3 of 9) © 2025 The Author(s). Advanced Optical Materials published by Wiley-VCH GmbH 21951071, 2025, 11, Downloaded from https://advanced.onlinelibrary.wiley.com/doi/10.1002/adom.202402606 by National Institute For, Wiley Online Library on [20/08/2025]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons Licensehttp://www.advancedsciencenews.comhttp://www.advopticalmat.dewww.advancedsciencenews.com www.advopticalmat.deFigure 2. a) Schematic illustration of propagating excitons in the chiral perovskite MBA2PbI4 and the resulting emission, monitored via time- andspatially-resolved photoluminescence microscopy. b) Transient PL in an S-type sample, exhibiting initially rapid decay followed by slower dynamics. Theblack trace corresponds to the instrument response function of the streak camera for the chosen measurement mode. c) Corresponding mean-freedisplacement as a function of time, demonstrating a rapid increase during the first 100′s ps characteristic for diffusive transport (regime I). It saturatesat later times indicating localization (regime II). The dotted black vertical line serves as a separation between the two regimes (I & II). The diffusioncoefficient D is extracted from the two-component propagation model according to Seitz et al.[30] and Folie et al.[44] of initial free propagation followed bylocalization into deep traps. Shaded area is a guide-to-the-eye. d) Diffusion coefficients as a function of excitation energy density demonstrating density-activated behavior. Estimated contribution of exciton-exciton annihilation (EEA) obtained from initial decay rate analysis shows negligible influence ofthis process. The black dashed line indicates the low-density diffusion coefficient D0. The inset shows density-dependent increase of the effective inter-trap separation 𝜆eff extracted from the fit. e) Schematic illustration of excitons initially propagating freely through the disorder potential (regime I) withan effective diffusion coefficient D, followed by localization at deep trap sites (regime II) accounting for a decrease of the effective diffusivity at latertimes.high diffusion in contrast to other 2D perovskites with differ-ent types of cations.[30,31] To test for non-linear processes at el-evated fluences,[31] we performed diffusion measurements asa function of excitation energy density on the S-type sample.The results are shown in Figure 2d from low densities to theregime where the excitation starts to reduce relative PL inten-sity due to photo-bleaching. The diffusion coefficients increaselinearly with excitation density, reaching up to 1.4 cm2 s−1 (cor-responding to an effective mobility of 55 cm2/Vs calculating us-ing the Einstein relation and classical approximation, presentedfor better comparison with electronic mobilities). This resultstarkly contrasts fluence-dependent measurements performedon (PEA)2PbI4, where diffusion coefficients remain nearly con-stant over more than three orders of magnitude in excitationdensity.[43,46] In general, density-activated diffusion can indicatethe emergence of non-linear processes, such as exciton-excitonannihilation (EEA), leading to a strong increase in the observeddiffusion coefficients and reduction of exciton lifetimes.[47,48]We estimate the EEA coefficient by analyzing the initial de-cay rate of the PL after the excitation (see SI, Section 10) anddetermine the resulting effective diffusion coefficients accord-ing to Deff = D0 +RA ⋅ n0 ⋅ w2016. Here, RA is the EEA coefficient, D0is the diffusion coefficient in the low-density limit and w0 thewidth of the laser profile derived from the full-width-at-half max-imum (FWHM) (w0 =FWHM2√ln2).[47] The determined RA of 8 ×10−3 cm2 s−1 would correspond to an increase of the effective dif-fusion coefficients of 0.15 cm2 s−1 over the studied density range,accounting only for a negligible part of the observed increase.A similar analysis of excitation density dependence in R- andRac-type samples yielded comparable results (see SI, Section 8).This means that exciton-exciton interactions only marginally con-tribute, and the non-linear diffusivity has a different origin in thestudied samples.Considering the presence of trapping sites that do not al-low for detrapping, the aforementioned trap model permits thedetermination of an effective inter-trap distance for 100% cap-ture probability.[30,49] The extracted values for the distance be-tween trapping states are presented in the inset of Figure 2das a function of excitation energy of the S-type sample. The ef-fective inter-trap distance is in the range of a few 100′s of nm.It increases linearly with the excitation density due to satura-tion, indicating that excitons are able to propagate further atAdv. Optical Mater. 2025, 13, 2402606 2402606 (4 of 9) © 2025 The Author(s). Advanced Optical Materials published by Wiley-VCH GmbH 21951071, 2025, 11, Downloaded from https://advanced.onlinelibrary.wiley.com/doi/10.1002/adom.202402606 by National Institute For, Wiley Online Library on [20/08/2025]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons Licensehttp://www.advancedsciencenews.comhttp://www.advopticalmat.dewww.advancedsciencenews.com www.advopticalmat.deFigure 3. a) Mean squared displacement extracted from transient photoluminescence spectra of an S-type sample as a function of time, recordedat different temperatures and a fixed excitation density of 0.5 μJ cm−2 per pulse. Rapid broadening of the emission area over the first few 100 pssuggests initial efficient diffusive transport of excitons that is followed by localization at all studied temperatures. Solid lines represent fits from thetwo-component propagation model, accounting for initial free propagation and subsequent capture of excitons at trapping sites. b) Corresponding PLtransients, demonstrating rapid recombination at early times, followed by decelerated decay dynamics in the localization regime. Solid lines representbiexponential fits to the data. c) Effective distance between trapping sites 𝜆eff as well as the d) diffusion coefficient D as a function of temperature. Anincrease of the effective inter-trap distance correlates with an increase of the diffusion coefficient, related to suppressed diffusion by earlier onset of thesubdiffusive regime at lower temperatures.elevated pump intensities before encountering active trappingsites. This finding implies that initial diffusion dynamics, incontrast to (PEA)2PbI4[30], are largely unaffected by deep trapdensity and are therefore more likely determined by the shal-low disorder potential of the material. The observed increas-ingly faster exciton transport at higher excitation densities couldthen be attributed to gradual state filling within the disorderpotential.[50] Figure 2e represent a schematic illustration of theproposed transport regimes: At early times after excitation, ex-citons are propagate freely with a diffusion coefficient D, deter-mined by the disordered energy landscape and intrinsic scat-tering with the phonons. After several 100′s ps, excitons arecaptured by trapping sites that are sufficiently deep to not al-low for detrapping and thus effectively decelerate the diffusivityin the second regime down to complete localization. At higherpump fluence, the deep traps are increasingly saturated, whilethe density-activated transport at early times is likely to stem fromgradual filling of the states within the disordered energy poten-tial with rising excitation density toward the excitonic mobilityedge.To better understand the exciton transport mechanisms, weperform temperature-dependent measurements at a fixed exci-tation density of 0.5 μJ cm−2 per pulse. Figure 3a depicts themean squared displacements ∆𝜎2 obtained from time- and spa-tially resolved measurements of an S-type sample at 100, 200 and300 K. Spatial broadening of the PL emission profiles over timeshows similar behavior from 100 K up to room temperature, witha regime of initial increase over a few 100′s ps, followed by stag-nation at later times. Both the initial expansion and the onsetof the subdiffusive regime are only weakly temperature depen-dent and the applied model offers a reasonable description ofthe experimental data at all studied temperatures. The PL tran-sients in Figure 3b as a function of temperature are consistentwith the two distinct regimes. The first regime is characterizedby fast exciton decay, while the second regime is determined bydecelerated recombination kinetics. The extracted values for theeffective inter-trap distance and the initial diffusion coefficient asa function of temperature are presented in Figure 3c,d, respec-tively. The diffusion coefficient slightly increases upon coolingdown the sample from room temperature down to 200 K, charac-teristic for the free propagation regime. It decreases for temper-atures below 200 K pointing at increased localization within theweakly disordered potential as the exciton transport starts to re-quire thermal activation in this regime.[40,51] Nonetheless, the ex-citons remain reasonably mobile even at 100 K with the absolutediffusion coefficients being about two times smaller comparedto the non-chiral 2D perovskites at similar conditions.[46] Thecorresponding changes in the inter-trap distance 𝜆eff is onlyweakly temperature-dependent with values between 250 and350 nm for the chosen pump fluence. This seems reasonable,since the trap distance should be primarily related to the spacingbetween trapping sites and their saturation. It also means that thecapture probability is only weakly dependent on the temperaturein the studied range as well.Adv. Optical Mater. 2025, 13, 2402606 2402606 (5 of 9) © 2025 The Author(s). Advanced Optical Materials published by Wiley-VCH GmbH 21951071, 2025, 11, Downloaded from https://advanced.onlinelibrary.wiley.com/doi/10.1002/adom.202402606 by National Institute For, Wiley Online Library on [20/08/2025]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons Licensehttp://www.advancedsciencenews.comhttp://www.advopticalmat.dewww.advancedsciencenews.com www.advopticalmat.deFigure 4. a) Summary of measured exciton diffusion coefficients recorded at low excitation density of 0.14 μJ cm−2 for all three sample types (R/Rac/S).The box plots display the interquartile range with the upper and lower quartiles representing the 25th and 75th percentiles, respectively. The line withineach box indicates the median value, while the dot in the center represents the average. The box plots are superimposed with the diffusion coefficientsof the corresponding individual measurements. b) Corresponding data for higher excitation fluence of 0.7 μJ cm−2. c) Absorbance spectra from photo-thermal deflection measurements using thick crystals. The disorder is characterized by the Urbach energies EU extracted from exponential fits (solidlines) and is correlated with the average diffusion coefficients.2.3. Exciton Diffusion Across Different ChiralitiesTo investigate how structural changes to the inorganic frame-work affect exciton transport properties, we monitor propagationin enantiomer-pure perovskites (R/S-types) and the racemic mix-ture (Rac-type) at two distinct excitation fluences. The diffusioncoefficient measurements recorded at low density (0.14 μJ cm−2)are summarized in Figure 4a, and the ones measured at higherexcitation energy fluence (0.7 μJ cm−2) are shown in Figure 4b.The box plots display the interquartile range, with upper andlower quartiles being the 25th and 75th percentiles. The hori-zontal line in the center of the box indicates the median diffu-sion coefficient value for each sample type. The individual mea-surements are presented with the box plots and reach values upto 0.9 cm2 s−1 even at low excitation densities while showing aconsiderable spread in all studied cases. We note that the ob-servation of substantial fluctuations in the diffusion coefficientis not unusual in 2D hybrid perovskites.[46] It also aligns withthe exciton peak’s energy fluctuations determined by hyperspa-tial microscopy (see Figure 1f). Nevertheless, median transportcoefficients show that the propagation of excitons in samples withenantiomer pure cations is faster than in racemic mixtures. Thisapplies to low and high excitation fluence with S-type samplesdemonstrating the highest overall diffusion coefficients.This observation points to structure-related differences in theexciton energy landscape, considering that chiral cations can in-troduce distortions to the inorganic framework. One of the met-rics that is particularly sensitive to that is the detection of Urbachenergies EU used to quantify disorder in the crystal lattice. Theparameter contains contributions from static and dynamic disor-der and usually ranges from a few to several tens of meV in chiral2D perovskites.[52] In amorphous semiconductors, the Urbachenergy is mainly dominated by static disorder caused by varia-tions in bond length and bond angle.[53] However, in perovskitessuch as MAPbI3, a substantial contribution can also arise fromthe dynamic component due to the cage vibrations of the inor-ganic framework.[52,54]To determine the disorder parameter EU in the studied racemicmixtures compared to enantiomer pure crystals, we thus em-ploy photo-thermal deflection spectroscopy using thick, large-area samples. The resulting absorbance spectra for all three sam-ple types are presented in Figure 4c. The spectra exhibit an expo-nential decrease toward lower energies from excitonic tail statescaused by defects in the crystal structure and lattice vibrations.[55]From exponential fits to the data, we extract Urbach energies of40.5 and 40.6 meV for R- and S-type samples and 48.6 meV for theracemic mixture. Overall, the obtained values for the Urbach en-ergies are somewhat larger compared to thin films of PEA2PbI4with EU = 35 meV[56] and MBA2PbI4 with EU = 29 meV.[25]Most importantly, they naturally explain differences in the ob-served median diffusion coefficients between enantiomer pure2D chiral perovskites and racemic mixtures.3. ConclusionIn summary, we have experimentally demonstrated efficient ex-citon diffusion in single crystals of chiral 2D perovskites withvalues on the order of 1 cm2 s−1 and the ability to efficiently trans-port energy over 100′s of nm at room temperature. We identifiedtwo distinct regimes of initially rapid propagation within the first0.5 ns and subsequent localization at later times. The studiedcrystals exhibited areas with homogeneous energy distributionon the order of several microns and tens of meV energy variationson larger spatial scales in accordance with the determined Ur-bach tail values. Moreover, excitons are found to propagate fasterin perovskites with enantiomer pure cations compared to theAdv. Optical Mater. 2025, 13, 2402606 2402606 (6 of 9) © 2025 The Author(s). Advanced Optical Materials published by Wiley-VCH GmbH 21951071, 2025, 11, Downloaded from https://advanced.onlinelibrary.wiley.com/doi/10.1002/adom.202402606 by National Institute For, Wiley Online Library on [20/08/2025]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons Licensehttp://www.advancedsciencenews.comhttp://www.advopticalmat.dewww.advancedsciencenews.com www.advopticalmat.deracemic mixture of both cations, which is linked to differencesin disorder. Finally, we find a strong fluence dependence of thetransport coefficients for all studied samples in contrast to otherperovskites with similar, yet achiral cations, with only negligibleimpact of exciton-exciton annihilation. We attribute this behav-ior to the gradual filling of both deep traps and the states withinthe disorder potential with increasing excitation density, leadingto increased fraction of freely propagating excitons. Observingcomparatively fast room temperature exciton transport despitethe presence of disorder renders chiral 2D perovskites an inter-esting platform for chiro-optical devices featuring mobile exci-ton quasiparticles. Alternatively, localization of excitons could beleveraged toward developing single-photon sources based on thisclass of chiral materials. Future developments toward increasedexcitonic mobility or the creation of exciton traps seem promis-ing in view of the flexibility in the 2D perovskites’ design.4. Experimental SectionSynthesis: PbO (99.999%) purchased from Alfa Aesar Puratonic,hyroiodic acid (57 wt.%) from TCI chemicals and R-, S- and rac-methylbenzylamine as well as diethyl ether from Sigma–Aldrich wereused. All chemicals were utilized without additional purification. The per-ovskites with R-, S- and rac-MBA cations were synthesized using the sameprocedure.[25] PbO (0.9 mmol) was dissolved in 5 ml of HI (57 wt.%) un-der N2 atmosphere and magnetic stirring, followed by dropwise additionof R-/S-/rac-methylbenzylamine (1.8 mmol), leading to the formation of aprecipitate. The reaction was then heated at 90 °C for 3 h to dissolve theprecipitate. After that, stirring was stopped and the reaction mixture wascooled at a rate of 5 °C/30 min until it reached 30 °C. The orange, needlelike crystals which formed overnight were vacuum filtered, washed withdiethyl ether and underwent purification in a Soxhlet apparatus to removeHI residues. Finally, the crystals were dried in a vacuum oven for 4 h priorto use.Exfoliation and Sample Fabrication: Single crystal 2D perovskite sam-ples were fabricated via micro-mechanical exfoliation from bulk crystalsand subsequent polymer-assisted stamping, following the technique out-lined by Castellanos-Gomez et al.[57] Hexagonal boron nitride (h-BN)crystals were cleaved and thinned down using Scotch Magic Tape. Thin-ner crystals were transferred onto PDMS (polydimethylsiloxane) and thenstamped onto preheated SiO2/Si substrates. Perovskite flakes were pro-duced in the same manner, transferred onto PDMS, aligned under a mi-croscope and then stamped onto the previously deposited h-BN layerat room temperature to prevent temperature-induced degradation. Thestack was completing by adding a second layer of h-BN, making sure thatthe perovskite was fully encapsulated from all sides for environmentalprotection.Optical Spectroscopy: All measurements were performed with thesamples mounted in a helium-flow cryostat (Cryovac) under high vac-uum conditions to prevent oxygen-induced degradation of the samples.A continuous-wave solid state laser at a wavelength of 405 nm was usedfor time-integrated photoluminescence measurements. The laser was fo-cused onto the sample using a glass-corrected 60x objective (Nikon), re-sulting in a spot size of ≈ 0.5 μm. The PL emission was filtered usinghard-coated edge-pass filters (ThorLabs), dispersed by a grating spectrom-eter and detected by a Peltier-cooled charge-coupled device camera (RoperScientific).For spatially and time-resolved measurements, 140 fs pulses of an80 MHz T-sapphire laser (Coherent) operating at 820 nm were frequencydoubled by an SHG crystal (APE) and focused onto the sample via aglass-corrected 60x objective to a spot of ≈0.5 μm. The emitted signalpassed through several spectral filters (ThorLabs) to eliminate reflectedand scattered laser light. It was then focused onto the slit of an imag-ing spectrometer (Princeton Instruments), reflected by a silver mirror forspatially-resolved measurements and imaged onto a streak camera detec-tor (Hamamatsu) providing temporal resolution. The streak camera wassynchronized with the frequency of the Ti:sapphire laser and operated insingle photon counting mode. For strong PL signals, neutral-density fil-ters were employed to reduce intensity and prevent-double counting inthe streak camera’s single-photon detection.Photothermal Deflection Spectroscopy: To assess large-area disorder,photo-thermal deflection spectroscopy (PDS) measurements were per-formed following established methods.[25,58] Millimeter-sized 2D per-ovskite flakes were mounted on UV-cured adhesive atop a quartz sub-strate and placed in a Fluorinert-filled cuvette. The sample was excitedby a monochromator-filtered 150 W xenon short arc lamp (Ushio), while a635 nm diode laser (ThorLabs) probed photothermal deflection. Absorbedlight induced local heating, altering the refractive index and deflectingthe laser beam, which was measured using a position-sensitive detector(ThorLabs) and lock-in amplifier (Amatec). The deflection directly corre-lated with film absorption, and Urbach energy was estimated by fitting thelow-energy absorption tail.Supporting InformationSupporting Information is available from the Wiley Online Library or fromthe author.AcknowledgementsFinancial support by the Deutsche Forschungsgemeinschaft (DFG) viaSPP2196 Priority Program (Project-ID: 424709454), CRC1415 (Project-ID: 417590517, B11) and the Würzburg-Dresden Cluster of Excellenceon Complexity and Topology in Quantum Matter ct.qmat (EXC 2147,Project-ID 390858490) is gratefully acknowledged. L.S. thanks the SãoPaulo Research Foundation (FAPESP), grants number 2020/04406-5 and2021/12104-1. L.S. and A.F.N. acknowledge the support from FAPESP(grant Numbers 2017/11631-2 and 2018/21401-7), Shell, and the strate-gic importance of the support given by ANP (Brazil’s National Oil, Natu-ral Gas and Biofuels Agency) through the R&D levy regulation. Y.V. thankthe DFG for funding in the framework of the Special Priority Program(SPP 2196) project PERFECT PVs (Project-ID: 424216076) and for gen-erous support within the framework of the GRK 2767 (project A7). Partof the work was performed within the frame of the M-ERA.NET projectPHANTASTIC (R.8003.22), supported by the SMWK. L.S. thanks the DFGfor funding via the Walter Benjamin Program (Project-ID: 558721159).K.W. and T.T. acknowledge support from the JSPS KAKENHI (Grant Num-bers 21H05233 and 23H02052) and World Premier International ResearchCenter Initiative (WPI), MEXT, Japan. Deutsche Forschungsgemeinschaft(DFG): SPP2196 (424709454, 424216076); CRC1415 (417590517); GRK2767; Excellence Cluster EXC 2147: 390858490; Sächsisches Staatsminis-terium für Wissenschaft, Kultur und Tourismus (SMWK): R.8003.22. TheSão Paulo Research Foundation (FAPESP): 2017/11631-2, 2018/21401-7,2020/04406-5, 2021/12104-1; Japan Society for the Promotion of Science(JSPS): 21H05233, 23H02052; Brazil’s National Oil, Natural Gas and Bio-fuels Agency (ANP); World Premier International Research Center Initia-tive (WPI).Open access funding enabled and organized by Projekt DEAL.Conflict of InterestThe authors declare no conflict of interest.Author ContributionsA.C. and S.T. conceived the experimental idea, together with L.S. and Y.V.S.T. encapsulated the samples, and performed the hyperspectral mappingAdv. Optical Mater. 2025, 13, 2402606 2402606 (7 of 9) © 2025 The Author(s). Advanced Optical Materials published by Wiley-VCH GmbH 21951071, 2025, 11, Downloaded from https://advanced.onlinelibrary.wiley.com/doi/10.1002/adom.202402606 by National Institute For, Wiley Online Library on [20/08/2025]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons Licensehttp://www.advancedsciencenews.comhttp://www.advopticalmat.dewww.advancedsciencenews.com www.advopticalmat.deand transient photoluminescence microscopy experiments. L.S, A.F.N.,and Y.V. synthesized the perovskite crystals. K.W. and T.T. provided h-BNcrystals. J.I.B. carried out the photothermal deflection spectroscopy mea-surements. D.H., J.D., Sh.Hu. Sv.Hö., and S.K. performed and analyzedcircularly polarized photoluminescence measurements. The manuscriptwas written by S.T. and A.C. with input from all authors.Data Availability StatementThe data that support the findings of this study are available from thecorresponding author upon reasonable request.Keywords2D perovskites, chirality, diffusion, excitons, transient microscopyReceived: September 26, 2024Revised: February 17, 2025Published online: March 28, 2025[1] T. Ishihara, J. Takahashi, T. Goto, Solid State Commun. 1989, 69, 933.[2] D. B. Mitzi, C. A. Feild, W. T. A. Harrison, A. M. Guloy, Nature 1994,369, 467.[3] E. A. Muljarov, S. G. Tikhodeev, N. A. Gippius, T. Ishihara, Phys. Rev.B 1995, 51, 14370.[4] S. Kumar, J. Jagielski, S. Yakunin, P. Rice, Y.-C. Chiu, M. Wang, G.Nedelcu, Y. Kim, S. Lin, E. J. G. Santos, M. V. Kovalenko, C.-J. Shih,ACS Nano 2016, 10, 9720.[5] H. Tsai, W. Nie, J. Blancon, C. C. Stoumpos, C. M. M. Soe, J. Yoo, J.Crochet, S. Tretiak, J. Even, A. Sadhanala, G. Azzellino, R. Brenes, P.M. Ajayan, V. Bulovíc, S. D. Stranks, R. H. Friend, M. G. Kanatzidis,A. D. Mohite, Adv. Mater. 2018, 30, 1704217.[6] N. Wang, L. Cheng, R. Ge, S. Zhang, Y. Miao, W. Zou, C. Yi, Y. Sun, Y.Cao, R. Yang, Y. Wei, Q. Guo, Y. Ke, M. Yu, Y. Jin, Y. Liu, Q. Ding, D.Di, L. Yang, G. Xing, H. Tian, C. Jin, F. Gao, R. H. Friend, J. Wang, W.Huang, Nature Photon 2016, 10, 699.[7] G. Grancini, M. K. Nazeeruddin, Nat. Rev. Mater. 2018, 4, 4.[8] H. Tsai, W. Nie, J.-C. Blancon, C. C. Stoumpos, R. Asadpour, B.Harutyunyan, A. J. Neukirch, R. Verduzco, J. J. Crochet, S. Tretiak, L.Pedesseau, J. Even, M. A. Alam, G. Gupta, J. Lou, P. M. Ajayan, M. J.Bedzyk, M. G. Kanatzidis, A. D. Mohite, Nature 2016, 536, 312.[9] D. B. Mitzi, in Progress in Inorganic Chemistry (Ed.: K. D. Karlin), Wiley,Hoboken, New Jersey 1999, pp. 1–121.[10] L. M. Herz, Annu. Rev. Phys. Chem. 2016, 67, 65.[11] T. Ishihara, J. Takahashi, T. Goto, Phys. Rev. B 1990, 42, 11099.[12] C. M. Mauck, W. A. Tisdale, Trends in Chemistry 2019, 1, 380.[13] F. Zhang, D. H. Kim, H. Lu, J.-S. Park, B. W. Larson, J. Hu, L. Gao, C.Xiao, O. G. Reid, X. Chen, Q. Zhao, P. F. Ndione, J. J. Berry, W. You,A. Walsh, M. C. Beard, K. Zhu, J. Am. Chem. Soc. 2019, 141, 5972.[14] X. Zhao, M. L. Ball, A. Kakekhani, T. Liu, A. M. Rappe, Y.-L. Loo, Nat.Commun. 2022, 13, 3970.[15] J. Ahn, E. Lee, J. Tan, W. Yang, B. Kim, J. Moon, Mater. Horiz. 2017, 4,851.[16] C. Han, A. J. Bradford, J. A. McNulty, W. Zhang, P. S. Halasyamani,A. M. Z. Slawin, F. D. Morrison, S. L. Lee, P. Lightfoot, Chem. Mater.2022, 34, 2458.[17] J. Lin, D. Chen, L. Yang, T. Lin, Y. Liu, Y. Chao, P. Chou, C. Chiu, AngewChem Int Ed 2021, 60, 21434.[18] J. Ahn, S. Ma, J.-Y. Kim, J. Kyhm, W. Yang, J. A. Lim, N. A. Kotov, J.Moon, J. Am. Chem. Soc. 2020, 142, 4206.[19] L. Scalon, Y. Vaynzof, A. F. Nogueira, C. C. Oliveira, Cell Reports Phys-ical Science 2023, 4, 101358.[20] G. Long, C. Jiang, R. Sabatini, Z. Yang, M. Wei, L. N. Quan, Q.Liang, A. Rasmita, M. Askerka, G. Walters, X. Gong, J. Xing, X. Wen,R. Quintero-Bermudez, H. Yuan, G. Xing, X. R. Wang, D. Song, O.Voznyy, M. Zhang, S. Hoogland, W. Gao, Q. Xiong, E. H. Sargent,Nature Photon 2018, 12, 528.[21] A. Pietropaolo, A. Mattoni, G. Pica, M. Fortino, G. Schifino, G.Grancini, Chem 2022, 8, 1231.[22] Z. Wang, C. Lin, K. Murata, A. S. A. Kamal, B. Lin, M. Chen, S. Tang,Y. Ho, C. Chen, C. Chen, H. Daiguji, K. Ishii, J. Delaunay, Adv. Mater.2023, 35, 2303203.[23] J. Ma, H. Wang, D. Li, Adv. Mater. 2021, 33, 2008785.[24] M. K. Jana, R. Song, H. Liu, D. R. Khanal, S. M. Janke, R. Zhao, C.Liu, Z. Valy Vardeny, V. Blum, D. B. Mitzi, Nat. Commun. 2020, 11,4699.[25] L. Scalon, J. Brunner, M. G. D. Guaita, R. Szostak, M. Albaladejo-Siguan, T. Kodalle, L. A. Guerrero-León, C. M. Sutter-Fella, C. C.Oliveira, Y. Vaynzof, A. F. Nogueira, Adv. Opt. Mater. 2024, 12,2300776.[26] K. Tanaka, T. Takahashi, T. Kondo, K. Umeda, K. Ema, T. Umebayashi,K. Asai, K. Uchida, N. Miura, Jpn. J. Appl. Phys. 2005, 44, 5923.[27] O. Yaffe, A. Chernikov, Z. M. Norman, Y. Zhong, A. Velauthapillai,A. Van Der Zande, J. S. Owen, T. F. Heinz, Phys. Rev. B 2015, 92,045414.[28] D. B. Mitzi, K. Chondroudis, C. R. Kagan, IBM J. Res. & Dev. 2001, 45,29.[29] H. Haug, S. W. Koch, Quantum Theory of the Optical and ElectronicProperties of Semiconductors, WORLD SCIENTIFIC, Singapore 2009.[30] M. Seitz, A. J. Magdaleno, N. Alcázar-Cano, M. Meléndez, T. J.Lubbers, S. W. Walraven, S. Pakdel, E. Prada, R. Delgado-Buscalioni,F. Prins, Nat. Commun. 2020, 11, 2035.[31] S. Deng, E. Shi, L. Yuan, L. Jin, L. Dou, L. Huang, Nat. Commun. 2020,11, 664.[32] D. G. Billing, A. Lemmerer, CrystEngComm 2006, 8, 686.[33] M. Seitz, P. Gant, A. Castellanos-Gomez, F. Prins, Nanomaterials2019, 9, 1120.[34] X. Wu, M. T. Trinh, D. Niesner, H. Zhu, Z. Norman, J. S. Owen,O. Yaffe, B. J. Kudisch, X.-Y. Zhu, J. Am. Chem. Soc. 2015, 137,2089.[35] J. Ma, C. Fang, C. Chen, L. Jin, J. Wang, S. Wang, J. Tang, D. Li, ACSNano 2019, 13, 3659.[36] L. Scalon, A. New, Z. Ge, N. Mondal, R. D. Campos, C. Quarti, D.Beljonne, A. F. Nogueira, A. A. Bakulin, Y. Vaynzof, Chem. Mater. 2024,36, 4331.[37] X. Li, J. M. Hoffman, M. G. Kanatzidis, Chem. Rev. 2021, 121,2230.[38] A. Neumann, J. Lindlau, L. Colombier, M. Nutz, S. Najmaei, J. Lou,A. D. Mohite, H. Yamaguchi, A. Högele, Nature Nanotech 2017, 12,329.[39] L. Niu, X. Liu, C. Cong, C. Wu, D. Wu, T. R. Chang, H. Wang, Q. Zeng,J. Zhou, X. Wang, W. Fu, P. Yu, Q. Fu, S. Najmaei, Z. Zhang, B. I.Yakobson, B. K. Tay, W. Zhou, H. T. Jeng, H. Lin, T. C. Sum, C. Jin, H.He, T. Yu, Z. Liu, Adv. Mater. 2015, 27, 7800.[40] A. D. Wright, C. Verdi, R. L. Milot, G. E. Eperon, M. A. Pérez-Osorio,H. J. Snaith, F. Giustino, M. B. Johnston, L. M. Herz, Nat. Commun.2016, 7, 11755.[41] N. S. Ginsberg, W. A. Tisdale, Annu. Rev. Phys. Chem. 2020, 71, 1.[42] G. M. Akselrod, P. B. Deotare, N. J. Thompson, J. Lee, W. A. Tisdale,M. A. Baldo, V. M. Menon, V. Bulovíc, Nat. Commun. 2014, 5, 3646.[43] X. Xiao, M. Wu, Z. Ni, S. Xu, S. Chen, J. Hu, P. N. Rudd, W. You, J.Huang, Adv. Mater. 2020, 32, 2004080.[44] B. D. Folie, J. A. Tan, J. Huang, P. C. Sercel, M. Delor, M. Lai, J. L.Lyons, N. Bernstein, A. L. Efros, P. Yang, N. S. Ginsberg, J. Phys. Chem.A 2020, 124, 1867.[45] M. Maiberg, T. Hölscher, S. Zahedi-Azad, R. Scheer, J. Appl. Phys.2015, 118, 105701.Adv. Optical Mater. 2025, 13, 2402606 2402606 (8 of 9) © 2025 The Author(s). Advanced Optical Materials published by Wiley-VCH GmbH 21951071, 2025, 11, Downloaded from https://advanced.onlinelibrary.wiley.com/doi/10.1002/adom.202402606 by National Institute For, Wiley Online Library on [20/08/2025]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons Licensehttp://www.advancedsciencenews.comhttp://www.advopticalmat.dewww.advancedsciencenews.com www.advopticalmat.de[46] J. D. Ziegler, J. Zipfel, B. Meisinger, M. Menahem, X. Zhu, T.Taniguchi, K. Watanabe, O. Yaffe, D. A. Egger, A. Chernikov, NanoLett. 2020, 20, 6674.[47] M. Kulig, J. Zipfel, P. Nagler, S. Blanter, C. Schüller, T. Korn, N.Paradiso, M. M. Glazov, A. Chernikov, Phys. Rev. Lett. 2018, 120,207401.[48] S. Mouri, Y. Miyauchi, M. Toh, W. Zhao, G. Eda, K. Matsuda, Phys.Rev. B 2014, 90, 155449.[49] M. Seitz, M. Meléndez, N. Alcázar-Cano, D. N. Congreve, R. Delgado-Buscalioni, F. Prins, Adv. Opt. Mater. 2021, 9, 2001875.[50] H. Jin, E. Debroye, M. Keshavarz, I. G. Scheblykin, M. B. J. Roeffaers,J. Hofkens, J. A. Steele, Mater. Horiz 2020, 7, 397.[51] B. I. Shklovskii, A. L. Ėfros, Electronic Properties of Doped Semicon-ductors, Springer-Verlag Berlin Heidelberg GmbH, Berlin Heidelberg2013.[52] E. Ugur, M. Ledinský, T. G. Allen, J. Holovský, A. Vlk, S. De Wolf, J.Phys. Chem. Lett. 2022, 13, 7702.[53] Y. Pan, F. Inam, M. Zhang, D. A. Drabold, Phys. Rev. Lett. 2008, 100,206403.[54] M. Ledinsky, T. Schönfeldová, J. Holovský, E. Aydin, Z. Hájková, L.Landová, N. Neyková, A. Fejfar, S. De Wolf, J. Phys. Chem. Lett. 2019,10, 1368.[55] V. M. Caselli, Z. Wei, M. M. Ackermans, E. M. Hutter, B. Ehrler, T. J.Savenije, ACS Energy Lett. 2020, 5, 3821.[56] Y. Zhang, R. Wang, Y. Li, Z. Wang, S. Hu, X. Yan, Y. Zhai, C. Zhang, C.Sheng, J. Phys. Chem. Lett. 2019, 10, 13.[57] A. Castellanos-Gomez, L. Vicarelli, E. Prada, J. O. Island, K. L.Narasimha-Acharya, S. I. Blanter, D. J. Groenendijk, M. Buscema, G.A. Steele, J. V. Alvarez, H. W. Zandbergen, J. J. Palacios, H. S. J. VanDer Zant, 2D Mater. 2014, 1, 025001.[58] D. Becker-Koch, B. Rivkin, F. Paulus, H. Xiang, Y. Dong, Z. Chen,A. A. Bakulin, Y. Vaynzof, J. Phys.: Condens. Matter 2019, 31,124001.[59] V. Mote, Y. Purushotham, B. Dole, J Theor Appl Phys 2012, 6, 6.[60] J. Zipfel, M. Kulig, R. Perea-Causín, S. Brem, J. D. Ziegler, R. Rosati, T.Taniguchi, K. Watanabe, M. M. Glazov, E. Malic, A. Chernikov, Phys.Rev. B 2020, 101, 115430.[61] Y. Dang, X. Liu, Y. Sun, J. Song, W. Hu, X. Tao, J. Phys. Chem. Lett.2020, 11, 1689.[62] M. Nespolo, A. H. Benahsene, J. Appl. Crystallogr. 2021, 54, 1594.[63] K. Wagner, Z. A. Iakovlev, J. D. Ziegler, M. Cuccu, T. Taniguchi,K. Watanabe, M. M. Glazov, A. Chernikov, Nano Lett. 2023, 23,4708.[64] E. Wietek, M. Florian, J. Göser, T. Taniguchi, K. Watanabe, A. Högele,M. M. Glazov, A. Steinhoff, A. Chernikov, Phys. Rev. Lett. 2024, 132,016202.[65] D. Sun, Y. Rao, G. A. Reider, G. Chen, Y. You, L. Brézin, A. R.Harutyunyan, T. F. Heinz, Nano Lett. 2014, 14, 5625.Adv. Optical Mater. 2025, 13, 2402606 2402606 (9 of 9) © 2025 The Author(s). Advanced Optical Materials published by Wiley-VCH GmbH 21951071, 2025, 11, Downloaded from https://advanced.onlinelibrary.wiley.com/doi/10.1002/adom.202402606 by National Institute For, Wiley Online Library on [20/08/2025]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons Licensehttp://www.advancedsciencenews.comhttp://www.advopticalmat.de Exciton Diffusion in Two-dimentional Chiral Perovskites 1. Introduction 2. Results 2.1. Hyperspectral Mapping of Chiral 2D Perovskites 2.2. Exciton Diffusion 2.3. Exciton Diffusion Across Different Chiralities 3. Conclusion 4. Experimental Section Supporting Information Acknowledgements Conflict of Interest Author Contributions Data Availability Statement Keywords